Converter swap, now dying in gear
01-15-2014, 04:20 PM
#1
Staging Lane
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Converter swap, now dying in gear Guys,
This may have been beat to death, but I did try searching and couldn't find anything quite like I'm dealing with. I recently had the trans. in my '00 Camaro rebuilt, along with installing a Transgo HD2 kit and a PTC 10" 3200 converter. Now, before any of this was done, the car ran fine with no issues or DTCs at all. I sent my pcm to Frost for a mail-order tune while the tranny was being gone thru.
Now, I have had the car back together and running for the last couple of weeks and it runs and shifts great, except for one small issue. When it's warmed up and idling around 500 in gear, it will sometimes die when trying to back up or pull forward at slow speeds, right when you let off the throttle. It idles at around 600-650 in park, but will sometimes hunt up and down 100 or so rpms. When in gear idling, however, it will idle from 500 down to 300 or so and back up to 500, and will do this a few times. It doesn't always die while in gear, but it does hunt up and down quite a bit. It seems to die when letting off the throttle at low speeds, especially if the steering wheel is being turned, putting strain on the p/s pump and the engine.
I have already emailed Steve and am awaiting his reply, as I know he is a very busy guy. I just thought that maybe others had some knowledge about this type of issue and could possibly shed some light on it.
Thanks in advance for any ideas or input!
This may have been beat to death, but I did try searching and couldn't find anything quite like I'm dealing with. I recently had the trans. in my '00 Camaro rebuilt, along with installing a Transgo HD2 kit and a PTC 10" 3200 converter. Now, before any of this was done, the car ran fine with no issues or DTCs at all. I sent my pcm to Frost for a mail-order tune while the tranny was being gone thru.
Now, I have had the car back together and running for the last couple of weeks and it runs and shifts great, except for one small issue. When it's warmed up and idling around 500 in gear, it will sometimes die when trying to back up or pull forward at slow speeds, right when you let off the throttle. It idles at around 600-650 in park, but will sometimes hunt up and down 100 or so rpms. When in gear idling, however, it will idle from 500 down to 300 or so and back up to 500, and will do this a few times. It doesn't always die while in gear, but it does hunt up and down quite a bit. It seems to die when letting off the throttle at low speeds, especially if the steering wheel is being turned, putting strain on the p/s pump and the engine.
I have already emailed Steve and am awaiting his reply, as I know he is a very busy guy. I just thought that maybe others had some knowledge about this type of issue and could possibly shed some light on it.
Thanks in advance for any ideas or input!
01-17-2014, 06:57 AM
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Staging Lane
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Thanks for the reply! Yeah, I'm waiting to hear back from Frost. I'm new to late-model fuel injection stuff, so any input is appreciated.
Thanks again!
Thanks again!
01-17-2014, 11:27 AM
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Lightweight converters will expose stability problems
in the idle RPM control loop. An over-rich idle condition
will destabilize the loop. Messing with the idle RPM
PID (not the scan tool "PID", but the tune file prop /
int / deriv coefficients) can make the control better
matched to the new motor-moment-of-inertia, but
I've only succeeded cut-and-try, never really understood
the workings of it (control theory is not my thing, and
the coefficients I'm told do not work in exactly classical
way).
Bumping idle RPM up to (say) 700-750RPM will also get
you up out of some sogginess, and this is an easy thing
to try just to get it drivable; you can work on pushing
it back down later. Presuming of course that you get
ahold of the tool to let you tweak at leisure.
in the idle RPM control loop. An over-rich idle condition
will destabilize the loop. Messing with the idle RPM
PID (not the scan tool "PID", but the tune file prop /
int / deriv coefficients) can make the control better
matched to the new motor-moment-of-inertia, but
I've only succeeded cut-and-try, never really understood
the workings of it (control theory is not my thing, and
the coefficients I'm told do not work in exactly classical
way).
Bumping idle RPM up to (say) 700-750RPM will also get
you up out of some sogginess, and this is an easy thing
to try just to get it drivable; you can work on pushing
it back down later. Presuming of course that you get
ahold of the tool to let you tweak at leisure.
01-17-2014, 03:18 PM
#6
Staging Lane
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Thanks, jimmyblue and Ed, for the replies!
I did speak with Frost a little earlier and he gave me a couple of things to try, namely opening the throttle blade screw about 1/8 of a turn and resetting the tps. I've got a cheap scan tool and I'm not sure how much info it will give me, as far as tps % #s go, but I will try it and see. I'm thinking that maybe I need to be looking into buying some sort of tuning hardware.
Thanks again for your help, guys!!
I did speak with Frost a little earlier and he gave me a couple of things to try, namely opening the throttle blade screw about 1/8 of a turn and resetting the tps. I've got a cheap scan tool and I'm not sure how much info it will give me, as far as tps % #s go, but I will try it and see. I'm thinking that maybe I need to be looking into buying some sort of tuning hardware.
Thanks again for your help, guys!!